The invention relates generally to electronic locking systems and deals more particularly with a management system for coding key cards and associated electronic locks to suit a variety of floor plans while providing substantial security and low maintenance.
Electronic locking systems previously known include key cards having magnetic data bits which represent a lock combination and other data, a central computer, a key card encoder for utilizing the data on the key cards, and a multiplicity of electronic locks. Each of the locks is equipped with a reader to read the magnetic data bits on the card and a microprocessor to process the data. If the lock access code matches a lock combination, the lock may be opened.
Electronic memory in the lock contains a plurality of the lock combinations associated respectively with a plurality of access levels. For example, in a hotel application, one combination stored in the lock may correspond to a key issued to a hotel patron and another combination may correspond to a key issued to a maid. There are drawbacks to this type of system. The number of combinations stored in the lock may be limited to comply with the memory capacity of such locks and security requirements. Even if a large number of combinations could be stored in each lock then the chance that a random, unauthorized card will contain one of such combinations is intolerably high. In addition, the key cards have limited data capacity.
In a difficult environment such as a dormitory where, for example, there is a locked external door controlling access to a common hallway and a plurality of locked internal dormitory rooms adjacent to the hallway, it may be desirable that the resident in each dormitory room have a key card which opens both the external door and the internal door leading to one dormitory room. In a previous known electronic locking system, each key card issued to a dormitory room resident had a unique code, each internal door lock stored the unique code of the resident, and the external door lock stored all the unique codes of all the residents.
Another previously known locking system adapted to a hotel includes a plurality of key cards. Each of the cards has a site code and a lock combination code. The site code unlocks all common doors at the site such as doors leading to a laundry room and the lock combination code unlocks only one individual door such as a dormitory room door. One problem with this system is that if one card is lost, the lock combinations in all the common doors must be changed to make the lost card inoperative and new cards must be issued to all of the card holders in order to maintain security.
Accordingly, a general object of the present invention is to provide an electronic, locking system which is flexible enough to allow card holders to have access through a plurality of doors having locks without jeopardizing the security of the system or requiring extensive replacement of key cards when a lock combination is changed.
A more specific object of the present invention is to provide a management system within the foregoing electronic locking system to encode key cards and designate lock combinations stored in associated locks.
Another specific object of the present invention is to provide an electronic locking system of the foregoing type which utilizes key cards and electronic locks having limited memory capability.
Other objects and advantages of the invention will become apparent from the following Detailed Description of the Preferred Embodiments and Claims.